DEV Community • 2026-04-19 15:23

FluentValidation en .NET 10 sin ensuciar tus entidades (Clean Architecture + MediatR)

Hola a Todos. Uno de los errores más comunes al construir aplicaciones en .NET es mezclar validaciones directamente en las entidades usando atributos como: [Required] [MaxLength] [EmailAddress] Aunque esto funciona, introduce varios problemas: ❌ Acopla el dominio a frameworks como ASP.NET ❌ Dificulta las pruebas unitarias ❌ Mezcla responsabilidades ❌ Reduce reutilización En este artículo v...

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4m read
The Mental Framework for Unlocking Agentic Workflows
DEV Community • 2026-04-19 15:22

The Mental Framework for Unlocking Agentic Workflows

📌 This article was originally presented as a talk at the inaugural Claude Code Manila meetup (March 5, 2026). After several requests from the attendees to share the slides, I've decided to instead publish them as a full article here. I figured that this was a more effective medium to share my insights on reliable long-running agentic workflows. The Beginner's Mark One of the most com...

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13m read
DEV Community • 2026-04-19 15:21

Three Vulnerabilities That Quietly Rewrote the Threat Model in 2025

Three Vulnerabilities That Quietly Rewrote the Threat Model in 2025 Every security vendor on the internet publishes a "top CVEs of the year" listicle. This isn't one of them. What I want to do is take three vulnerabilities from 2025 that, individually, look like another round of patch-and-move-on — and show why, taken together, they describe a shift that most teams haven't internalized...

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10m read
Hacker News: Front Page • 2026-04-19 15:20

Notion leaks email addresses of all editors of any public page

Article URL: https://twitter.com/weezerOSINT/status/2045849358462222720 Comments URL: https://news.ycombinator.com/item?id=47824945 Points: 5 # Comments: 0

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DEV Community • 2026-04-19 15:19

Server builds, wallet signs, webhooks confirm — a non-custodial Web3 checkout pattern with Solana

I've been building a Solana checkout flow. The core challenge: the server needs to control the terms of every payment — the amount, the recipient, the audit trail — without ever holding a private key. This post documents the pattern I landed on: Checkout session with TTL and CSRF protection Atomic token invalidation to prevent TOCTOU race conditions A server-side pending record (similar to Stri...

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1m read
DEV Community • 2026-04-19 15:19

SQL for Beginners: Essential Concepts Made Simple

SQL stands for Structured Query Language. It is the standard language used to communicate with databases. Think of SQL as the "English" you speak to a database when you want to get information, add new data, update records, or delete something. SQL allows you to do 4 main things (often remembered as CRUD) where C represents Create, R represents READ while U represents Update and D represents Delet...

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3m read
EcoSense AI: Know Your Carbon Footprint in 60 Seconds
DEV Community • 2026-04-19 15:18

EcoSense AI: Know Your Carbon Footprint in 60 Seconds

This is a submission for Weekend Challenge: Earth Day Edition What I Built EcoSense AI is an AI-powered carbon footprint analyzer that helps people understand their environmental impact through a simple, beautiful 4-step questionnaire. Users answer questions about their: 🚗 Transportation — commute method & distance 🍽️ Diet — from heavy meat to vegan ⚡ Home Energy — fossil fuels ...

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3m read
Built “Event Buddy AI” in a day for PromptWars (Google Antigravity + Cloud Run)
DEV Community • 2026-04-19 15:17

Built “Event Buddy AI” in a day for PromptWars (Google Antigravity + Cloud Run)

_Hackathons always scared me a bit. Too many ideas, too little time, and lots of “pro” developers showing crazy projects. PromptWars changed that. This time, I decided to keep it simple and actually finish something. I picked the Physical Event Experience challenge and built a tiny web app called Event Buddy AI. The problem I wanted to solve At any physical event, people are always confused: “...

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3m read
DEV Community • 2026-04-19 15:14

AI Memory Systems: Everything You Need to Know

If you have built anything with ChatGPT, Claude, or any large language model in the past year, you have probably hit this wall: the AI forgets what you told it three messages ago. You explain your preferences, share context about your project, and then have to repeat it all over again in the next conversation. This is not a bug. It is how these systems work by default. But it does not have to sta...

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22m read
DEV Community • 2026-04-19 15:14

The Opus 4.7 Tokenizer Ate Your Budget (30-Second Fix)

Opus 4.7 uses a new tokenizer. Same code, same prompt, 25-35% more tokens. If your Claude bill jumped this week, that's why. The Fix # Before: everything goes through Opus response = client.messages.create(model="claude-opus-4-6", ...) # After: match the model to the task def pick_model(task_type): if task_type in ["rename", "format", "docstring"]: return "claude-haiku-...

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1m read
How I packaged offline AI, Flask, and Cryptography into a single Python executable 🚀
DEV Community • 2026-04-19 15:09

How I packaged offline AI, Flask, and Cryptography into a single Python executable 🚀

If you have ever tried to share a complex Python project with a friend or a security analyst, you know the pain. You hand them the code, and within five minutes, their terminal is throwing errors about missing pip packages, conflicting library versions, or broken machine learning dependencies. As a Computer Science student, I recently ran into this exact wall while building my open-source digi...

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3m read
Hacker News: Front Page • 2026-04-19 15:09

Russia's doping program is run by the same FSB team that poisoned Navalny

Article URL: https://theins.press/en/inv/291614 Comments URL: https://news.ycombinator.com/item?id=47824874 Points: 26 # Comments: 4

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1m read
Canvas Apps Authoring MCP: Testing what it can do
DEV Community • 2026-04-19 15:08

Canvas Apps Authoring MCP: Testing what it can do

So Canvas Apps Authoring MCP is here in Preview. I have no doubt that it can generate something, but we need a timesaver, not more hours cleaning up after it. And I showed up with a list of demands >>>>> My checklist follow naming convention use color/layout scheme from named formulas see (and use) custom components not main point, but add accessibility labels (the m...

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5m read
GitHub Copilot AI Agents: The Secret to 10x Engineering in 2026
DEV Community • 2026-04-19 15:07

GitHub Copilot AI Agents: The Secret to 10x Engineering in 2026

In this article, I’ll show you how to unlock the full power of GitHub Copilot agents inside VS Code. There are actually three main types of Copilot agents-most people only know about one, but I’m going to show you all of them. By the end, you’ll be able to create custom agents that act as your own specialized “sub-agents.” Getting Started: The Setup Before we dive into the agents, make...

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5m read
Hacker News: Front Page • 2026-04-19 15:04

Discord Read Receipts Exploit: When, How Often, How Long

Article URL: https://paul.koeck.dev/writeups/discord-read-receipts Comments URL: https://news.ycombinator.com/item?id=47824832 Points: 4 # Comments: 0

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1m read
How I Automate Jira Tickets Investigation using Claude Code & MCP
DEV Community • 2026-04-19 15:03

How I Automate Jira Tickets Investigation using Claude Code & MCP

As a software engineer, I hate context switching. Investigating a Jira ticket usually means bouncing between Jira for the context, Confluence for the high-level logic, the Codebase for the actual implementation, and finally Slack to ping the reporter about blockers/additional questions. It takes time, breaks flow, and is incredibly tedious. So, I decided to automate the entire process using Claude...

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2m read
DEV Community • 2026-04-19 15:02

CQRS

CQRS: Simplifying Complex Applications with Command Query Responsibility Segregation. CQRS: Benefits, Challenges & Real-World Use. Introduction Modern applications need to handle large data and high traffic efficiently. Traditional architectures often struggle with performance and scalability. This is where CQRS (Command Query Responsibility Segregation) comes in. What is CQRS? CQRS stands...

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1m read
From ChatGPT System Prompt to a Music App
DEV Community • 2026-04-19 15:02

From ChatGPT System Prompt to a Music App

Three technical decisions from productizing a pattern I'd been using by hand. For a while I'd been using ChatGPT as a music curator. Not a tool, not an app — a conversation. A system prompt describing the kind of listener I was and how I wanted to think about records. After listening to something I'd write a few sentences about how the record landed, paste them into the thread, and ask ...

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5m read
How I used Python to turn a cheap 20$ smartwatch into a PC remote!
DEV Community • 2026-04-19 15:01

How I used Python to turn a cheap 20$ smartwatch into a PC remote!

We’ve all seen them—those $20 Smartwatches on Amazon or AliExpress. They look decent, but they are locked behind sketchy, ad-filled mobile apps. I wanted to see if I could "liberate" the hardware. Today, I’m open-sourcing Synod: A Python-based engine that turns any generic BLE wearable into a dedicated macro deck for your PC. Why build this? Most smartwatches send "UI Notifications" over Bluet...

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2m read
Mastering Modern Hiring Demonstration: Using Docling and PostgreSQL by Bob to Build a Local Candidate RAG Database
DEV Community • 2026-04-19 14:53

Mastering Modern Hiring Demonstration: Using Docling and PostgreSQL by Bob to Build a Local Candidate RAG Database

This blog post’s idea is to explore how to bridge the gap between traditional relational data and unstructured documents to create a powerful hypothetical recruitment tool. Introduction The Candidate RAG System leverages a sophisticated technology stack to turn a folder of resumes into an interactive, searchable knowledge base. By combining Docling’s hierarchical document processing ...

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14m read
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